diff mbox series

[bpf-next,v3,1/2] libbpf: Add pathname_concat() helper

Message ID 1663555725-17016-1-git-send-email-wangyufen@huawei.com (mailing list archive)
State Superseded
Delegated to: BPF
Headers show
Series [bpf-next,v3,1/2] libbpf: Add pathname_concat() helper | expand

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Commit Message

wangyufen Sept. 19, 2022, 2:48 a.m. UTC 
Move snprintf and len check to common helper pathname_concat() to make the
code simpler.

Signed-off-by: Wang Yufen <wangyufen@huawei.com>
---
 tools/lib/bpf/libbpf.c | 76 +++++++++++++++++++-------------------------------
 1 file changed, 29 insertions(+), 47 deletions(-)

Comments

Andrii Nakryiko Sept. 22, 2022, 12:35 a.m. UTC | #1 
On Sun, Sep 18, 2022 at 7:28 PM Wang Yufen <wangyufen@huawei.com> wrote:
>
> Move snprintf and len check to common helper pathname_concat() to make the
> code simpler.
>
> Signed-off-by: Wang Yufen <wangyufen@huawei.com>
> ---
>  tools/lib/bpf/libbpf.c | 76 +++++++++++++++++++-------------------------------
>  1 file changed, 29 insertions(+), 47 deletions(-)
>
> diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
> index 3ad1392..43a530d 100644
> --- a/tools/lib/bpf/libbpf.c
> +++ b/tools/lib/bpf/libbpf.c
> @@ -2096,19 +2096,30 @@ static bool get_map_field_int(const char *map_name, const struct btf *btf,
>         return true;
>  }
>
> +static int pathname_concat(const char *path, const char *name, char *buf, size_t buflen)
> +{
> +       int len;
> +
> +       len = snprintf(buf, buflen, "%s/%s", path, name);
> +       if (len < 0)
> +               return -EINVAL;
> +       if (len >= buflen)
> +               return -ENAMETOOLONG;
> +
> +       return 0;
> +}
> +
>  static int build_map_pin_path(struct bpf_map *map, const char *path)
>  {
>         char buf[PATH_MAX];
> -       int len;
> +       int err;
>
>         if (!path)
>                 path = "/sys/fs/bpf";
>
> -       len = snprintf(buf, PATH_MAX, "%s/%s", path, bpf_map__name(map));
> -       if (len < 0)
> -               return -EINVAL;
> -       else if (len >= PATH_MAX)
> -               return -ENAMETOOLONG;
> +       err = pathname_concat(path, bpf_map__name(map), buf, PATH_MAX);

sizeof(buf) instead of PATH_MAX?

> +       if (err)
> +               return err;
>
>         return bpf_map__set_pin_path(map, buf);
>  }
> @@ -7961,17 +7972,9 @@ int bpf_object__pin_maps(struct bpf_object *obj, const char *path)
>                         continue;
>
>                 if (path) {
> -                       int len;
> -
> -                       len = snprintf(buf, PATH_MAX, "%s/%s", path,
> -                                      bpf_map__name(map));
> -                       if (len < 0) {
> -                               err = -EINVAL;
> -                               goto err_unpin_maps;
> -                       } else if (len >= PATH_MAX) {
> -                               err = -ENAMETOOLONG;
> +                       err = pathname_concat(path, bpf_map__name(map), buf, PATH_MAX);

same, let's not hardcode constants we don't need to hardcode, just do
sizeof(buf)

> +                       if (err)
>                                 goto err_unpin_maps;
> -                       }
>                         sanitize_pin_path(buf);
>                         pin_path = buf;
>                 } else if (!map->pin_path) {
> @@ -8009,14 +8012,9 @@ int bpf_object__unpin_maps(struct bpf_object *obj, const char *path)
>                 char buf[PATH_MAX];
>
>                 if (path) {
> -                       int len;
> -
> -                       len = snprintf(buf, PATH_MAX, "%s/%s", path,
> -                                      bpf_map__name(map));
> -                       if (len < 0)
> -                               return libbpf_err(-EINVAL);
> -                       else if (len >= PATH_MAX)
> -                               return libbpf_err(-ENAMETOOLONG);
> +                       err = pathname_concat(path, bpf_map__name(map), buf, PATH_MAX);

ditto here and all the cases below

> +                       if (err)
> +                               return err;
>                         sanitize_pin_path(buf);
>                         pin_path = buf;
>                 } else if (!map->pin_path) {
> @@ -8034,6 +8032,7 @@ int bpf_object__unpin_maps(struct bpf_object *obj, const char *path)
>  int bpf_object__pin_programs(struct bpf_object *obj, const char *path)
>  {
>         struct bpf_program *prog;
> +       char buf[PATH_MAX];
>         int err;
>
>         if (!obj)
> @@ -8045,17 +8044,9 @@ int bpf_object__pin_programs(struct bpf_object *obj, const char *path)
>         }
>
>         bpf_object__for_each_program(prog, obj) {
> -               char buf[PATH_MAX];
> -               int len;
> -
> -               len = snprintf(buf, PATH_MAX, "%s/%s", path, prog->name);
> -               if (len < 0) {
> -                       err = -EINVAL;
> -                       goto err_unpin_programs;
> -               } else if (len >= PATH_MAX) {
> -                       err = -ENAMETOOLONG;
> +               err = pathname_concat(path, prog->name, buf, PATH_MAX);
> +               if (err)
>                         goto err_unpin_programs;
> -               }
>
>                 err = bpf_program__pin(prog, buf);
>                 if (err)
> @@ -8066,13 +8057,7 @@ int bpf_object__pin_programs(struct bpf_object *obj, const char *path)
>
>  err_unpin_programs:
>         while ((prog = bpf_object__prev_program(obj, prog))) {
> -               char buf[PATH_MAX];
> -               int len;
> -
> -               len = snprintf(buf, PATH_MAX, "%s/%s", path, prog->name);
> -               if (len < 0)
> -                       continue;
> -               else if (len >= PATH_MAX)
> +               if (pathname_concat(path, prog->name, buf, PATH_MAX))
>                         continue;
>
>                 bpf_program__unpin(prog, buf);
> @@ -8091,13 +8076,10 @@ int bpf_object__unpin_programs(struct bpf_object *obj, const char *path)
>
>         bpf_object__for_each_program(prog, obj) {
>                 char buf[PATH_MAX];
> -               int len;
>
> -               len = snprintf(buf, PATH_MAX, "%s/%s", path, prog->name);
> -               if (len < 0)
> -                       return libbpf_err(-EINVAL);
> -               else if (len >= PATH_MAX)
> -                       return libbpf_err(-ENAMETOOLONG);
> +               err = pathname_concat(path, prog->name, buf, PATH_MAX);
> +               if (err)
> +                       return libbpf_err(err);
>
>                 err = bpf_program__unpin(prog, buf);
>                 if (err)
> --
> 1.8.3.1
>
Andrii Nakryiko Sept. 22, 2022, 12:41 a.m. UTC | #2 
On Sun, Sep 18, 2022 at 7:28 PM Wang Yufen <wangyufen@huawei.com> wrote:
>
> Move snprintf and len check to common helper pathname_concat() to make the
> code simpler.
>
> Signed-off-by: Wang Yufen <wangyufen@huawei.com>
> ---
>  tools/lib/bpf/libbpf.c | 76 +++++++++++++++++++-------------------------------
>  1 file changed, 29 insertions(+), 47 deletions(-)
>

[...]

> @@ -8009,14 +8012,9 @@ int bpf_object__unpin_maps(struct bpf_object *obj, const char *path)
>                 char buf[PATH_MAX];
>
>                 if (path) {
> -                       int len;
> -
> -                       len = snprintf(buf, PATH_MAX, "%s/%s", path,
> -                                      bpf_map__name(map));
> -                       if (len < 0)
> -                               return libbpf_err(-EINVAL);
> -                       else if (len >= PATH_MAX)
> -                               return libbpf_err(-ENAMETOOLONG);
> +                       err = pathname_concat(path, bpf_map__name(map), buf, PATH_MAX);
> +                       if (err)
> +                               return err;

also keep libbpf_err() as well, it sets errno properly

>                         sanitize_pin_path(buf);
>                         pin_path = buf;
>                 } else if (!map->pin_path) {
> @@ -8034,6 +8032,7 @@ int bpf_object__unpin_maps(struct bpf_object *obj, const char *path)
>  int bpf_object__pin_programs(struct bpf_object *obj, const char *path)
>  {
>         struct bpf_program *prog;
> +       char buf[PATH_MAX];
>         int err;
>
>         if (!obj)

[...]
wangyufen Sept. 22, 2022, 1:50 a.m. UTC | #3 
在 2022/9/22 8:41, Andrii Nakryiko 写道:
> On Sun, Sep 18, 2022 at 7:28 PM Wang Yufen <wangyufen@huawei.com> wrote:
>> Move snprintf and len check to common helper pathname_concat() to make the
>> code simpler.
>>
>> Signed-off-by: Wang Yufen <wangyufen@huawei.com>
>> ---
>>   tools/lib/bpf/libbpf.c | 76 +++++++++++++++++++-------------------------------
>>   1 file changed, 29 insertions(+), 47 deletions(-)
>>
> [...]
>
>> @@ -8009,14 +8012,9 @@ int bpf_object__unpin_maps(struct bpf_object *obj, const char *path)
>>                  char buf[PATH_MAX];
>>
>>                  if (path) {
>> -                       int len;
>> -
>> -                       len = snprintf(buf, PATH_MAX, "%s/%s", path,
>> -                                      bpf_map__name(map));
>> -                       if (len < 0)
>> -                               return libbpf_err(-EINVAL);
>> -                       else if (len >= PATH_MAX)
>> -                               return libbpf_err(-ENAMETOOLONG);
>> +                       err = pathname_concat(path, bpf_map__name(map), buf, PATH_MAX);
>> +                       if (err)
>> +                               return err;
> also keep libbpf_err() as well, it sets errno properly
>
>>                          sanitize_pin_path(buf);
>>                          pin_path = buf;
>>                  } else if (!map->pin_path) {
>> @@ -8034,6 +8032,7 @@ int bpf_object__unpin_maps(struct bpf_object *obj, const char *path)
>>   int bpf_object__pin_programs(struct bpf_object *obj, const char *path)
>>   {
>>          struct bpf_program *prog;
>> +       char buf[PATH_MAX];
>>          int err;
>>
>>          if (!obj)
> [...]


Thanks for your comments， will send v4.
diff mbox series

Patch

diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 3ad1392..43a530d 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -2096,19 +2096,30 @@  static bool get_map_field_int(const char *map_name, const struct btf *btf,
 	return true;
 }
 
+static int pathname_concat(const char *path, const char *name, char *buf, size_t buflen)
+{
+	int len;
+
+	len = snprintf(buf, buflen, "%s/%s", path, name);
+	if (len < 0)
+		return -EINVAL;
+	if (len >= buflen)
+		return -ENAMETOOLONG;
+
+	return 0;
+}
+
 static int build_map_pin_path(struct bpf_map *map, const char *path)
 {
 	char buf[PATH_MAX];
-	int len;
+	int err;
 
 	if (!path)
 		path = "/sys/fs/bpf";
 
-	len = snprintf(buf, PATH_MAX, "%s/%s", path, bpf_map__name(map));
-	if (len < 0)
-		return -EINVAL;
-	else if (len >= PATH_MAX)
-		return -ENAMETOOLONG;
+	err = pathname_concat(path, bpf_map__name(map), buf, PATH_MAX);
+	if (err)
+		return err;
 
 	return bpf_map__set_pin_path(map, buf);
 }
@@ -7961,17 +7972,9 @@  int bpf_object__pin_maps(struct bpf_object *obj, const char *path)
 			continue;
 
 		if (path) {
-			int len;
-
-			len = snprintf(buf, PATH_MAX, "%s/%s", path,
-				       bpf_map__name(map));
-			if (len < 0) {
-				err = -EINVAL;
-				goto err_unpin_maps;
-			} else if (len >= PATH_MAX) {
-				err = -ENAMETOOLONG;
+			err = pathname_concat(path, bpf_map__name(map), buf, PATH_MAX);
+			if (err)
 				goto err_unpin_maps;
-			}
 			sanitize_pin_path(buf);
 			pin_path = buf;
 		} else if (!map->pin_path) {
@@ -8009,14 +8012,9 @@  int bpf_object__unpin_maps(struct bpf_object *obj, const char *path)
 		char buf[PATH_MAX];
 
 		if (path) {
-			int len;
-
-			len = snprintf(buf, PATH_MAX, "%s/%s", path,
-				       bpf_map__name(map));
-			if (len < 0)
-				return libbpf_err(-EINVAL);
-			else if (len >= PATH_MAX)
-				return libbpf_err(-ENAMETOOLONG);
+			err = pathname_concat(path, bpf_map__name(map), buf, PATH_MAX);
+			if (err)
+				return err;
 			sanitize_pin_path(buf);
 			pin_path = buf;
 		} else if (!map->pin_path) {
@@ -8034,6 +8032,7 @@  int bpf_object__unpin_maps(struct bpf_object *obj, const char *path)
 int bpf_object__pin_programs(struct bpf_object *obj, const char *path)
 {
 	struct bpf_program *prog;
+	char buf[PATH_MAX];
 	int err;
 
 	if (!obj)
@@ -8045,17 +8044,9 @@  int bpf_object__pin_programs(struct bpf_object *obj, const char *path)
 	}
 
 	bpf_object__for_each_program(prog, obj) {
-		char buf[PATH_MAX];
-		int len;
-
-		len = snprintf(buf, PATH_MAX, "%s/%s", path, prog->name);
-		if (len < 0) {
-			err = -EINVAL;
-			goto err_unpin_programs;
-		} else if (len >= PATH_MAX) {
-			err = -ENAMETOOLONG;
+		err = pathname_concat(path, prog->name, buf, PATH_MAX);
+		if (err)
 			goto err_unpin_programs;
-		}
 
 		err = bpf_program__pin(prog, buf);
 		if (err)
@@ -8066,13 +8057,7 @@  int bpf_object__pin_programs(struct bpf_object *obj, const char *path)
 
 err_unpin_programs:
 	while ((prog = bpf_object__prev_program(obj, prog))) {
-		char buf[PATH_MAX];
-		int len;
-
-		len = snprintf(buf, PATH_MAX, "%s/%s", path, prog->name);
-		if (len < 0)
-			continue;
-		else if (len >= PATH_MAX)
+		if (pathname_concat(path, prog->name, buf, PATH_MAX))
 			continue;
 
 		bpf_program__unpin(prog, buf);
@@ -8091,13 +8076,10 @@  int bpf_object__unpin_programs(struct bpf_object *obj, const char *path)
 
 	bpf_object__for_each_program(prog, obj) {
 		char buf[PATH_MAX];
-		int len;
 
-		len = snprintf(buf, PATH_MAX, "%s/%s", path, prog->name);
-		if (len < 0)
-			return libbpf_err(-EINVAL);
-		else if (len >= PATH_MAX)
-			return libbpf_err(-ENAMETOOLONG);
+		err = pathname_concat(path, prog->name, buf, PATH_MAX);
+		if (err)
+			return libbpf_err(err);
 
 		err = bpf_program__unpin(prog, buf);
 		if (err)